Inside Sandra Bullock's Heartbreak

In the wake of a scandal that has rocked her marriage, Sandra Bullock is quietly determining her next move, say friends.

Stunned by revelations that her husband Jesse James cheated with tattoo model Michelle McGee, Bullock "needs time to grieve and process what has happened," a close friend tells PEOPLE in its new cover story, on newsstands Friday.

The friend says Bullock, 45, learned of her husband's betrayal just eight days after her triumphant March 7 Oscar win.